Stain removal



Patented" Nov; 26,1935

" '7 RE OVAL I ,Niagara Falls, N. Y., assignorgto' I James F White The Mathieson Alkali'Works, 1110.; New *York,

' N. Y., a corporation of Virginia I No Drawing.

This invention relates to an improved stain removing process comprising treatment stained material with a chlorite, such as chlorite or calciumchlorite, and oxalic aqueous solution. an improved stain removing. composition.

Chlorites ar at the same time are destructive action with r salts 'of chlorous acid H0102.

Incarrying out the process of theinventlon, g the stained material is subjected to-treatment with aqueous solutions containing a chlorite, or v I the chlorite radical, and oxalic acid. 'I'helstained" single aqueous solution ontai rite and the oxalic i may be subjected an aqueoussoluti ous solution containing the oxalic acid,

alkaline or neutral but with advantage is'acid. Such acidity may be supplied bysuch acids or acid salts.

pie, from 10-25 grams per liter of sodium and from 10-25 grams per liter of oxalic acid;

The process and composition of the invention are of special value and application in The invention also includes e effective in removing stains and free from tendencies toward espect I particularly to cotton and rayon textiles. The oxalic acid, simlz larly, is effective in removing stains, operating in a peculiarly efiective manner in conjunction.

with the chlorites in this respect. Although the I oxalic acid has reducing properties it is oxidized but slowly by the-'chlorites. The chlorite radical and the oxalate radical are the components of these reagents essential to the process of the in- I I vention. The term chlorite is used in this applicalcium. chlorite is bestavoided. cation in its strict chemical sense to define the. q

The treating solutions may contain, for exam 'Application February 19, 1932 t SerialZ No. 594,153- II i chlorite, such'as sodium chlorite or calcium ch10 tive, the chlorite solution may'contain; for 'exg and'the-oxalicaci'd solution may contain, for example, about 6 grams perliter of oxalicacid. 10 V '1' The chlorites of the alkalirmetalsand the a1ka-' spect' to each other to avoid undesired preci I tion in the treating solution or solutions. j For The stainremoving compositionfoithe inven- ,uon comprises dry'gmixtures, oi -,these chlorites, 20* oxalate salts, such as sodiumoxalate, and acid agents 'such as 'boric acid,'sodlum acid su lfate--;' potassium acid phosphateand sodium silico' fiuor quiredquantity ofqstain removing solution, small one part of sodium o'xalatean'd tw tassium dihydrogen'phosphate, '11 claim:

subjecting the stain to treatment with an aqueous" solution comprising a chlorite. from the group.

earth metal chlorites, anda substance from the oxalates.

may be 2.-A sta1n removing pr'ocesswhich 1cornD 'Q ses' aqueous solution comprising a-chlorite' from} the Y group consisting of alkalij-metal-chlorites and alfrom the groupiconsistingof oxalic acid and water-soluble oxalates. t V I 3. A stain removing composition which com"- prises a dry mixture, of a water-soluble chlorite chlorite the resoluble-oxalate, and an acidifying agent.

JAMES n-wm'rn.

treatment'with anaqueous solution containing: theoxalic acid. i Inapplying thelatter alterna -m 'ample, about 16 grams per liter of so'dium chlorite" I line-earth-metals are useful in "carrying out the: invention. The several age'nts used in-anycne embodimentof the process are chosen 'withrepita- 15 example, the use of a sulfate inconjunction with r II I 'ide', These mixtures are-'st'ablaandg simply by material may be subjected "to treatmentwith a; solution in water, may; be used to prepareany'reQZS if;

ning both the chloe stained material treatment, with I containing the chlorite and a separate aqueouss'clution containing the oxalic acid. The aqueous solution containing oxalic acid may be an aqueous solution of oxalic acid or of an oxalate, such as sodium oxalate, and an acid or acid salt, such as acetic acidor, when'used in conjunction with sodium chlorite for'exainplasodium acid sulfate, potassium acid'phosphate .or sodium silico fluoride. The aqueous solution con-I taining a chlorite, when separate from the aqueor large. Thecompositionmaycomprise; forex ample, one part (by weight) oisodium'chIorite,

1. A' stain removing-process: which comprises consisting, or alkali-metal chlorltes and alkaline- 35 I group consistingloi oxalic acid-and water solubleb subjecting the stain totreatmentwith acid 40 kaline-earth-metal chlorites, and a substance from. the group consisting of'alkal i-me'tal .chlo- I rites and al-kalineearth-metal chlorites, a-water; t 

